1. Beihang University,School of Cyber Science and Technology,Beijing,China,100191
2. Shijiazhuang Railway University,School of Information Science and Technology,Shijiazhuang,China,050043
3. Shijiazhuang Institute of Railway Technology,Shijiazhuang,China,050041
4. Zhongke Zidong Information Technology (Beijing) Co. Ltd,Beijing,China